Think of John Adams and you might immediately think: minimalist. One third of a triumvirate of US composers – alongside Philip Glass and Steve Reich – who devise music based on repetition and gradual change, hypnotic soundscapes and propulsive rhythms. Well, you wouldn’t be entirely wrong. Certainly, two recent high-profile outings for Adams’ music in Scotland – the Harmonium Project that launched the 2015 Edinburgh International Festival, and Scottish Opera’s recent staging of his first opera, Nixon in China – go a long way to confirming that minimalist reputation.

But strictly speaking, that’s pretty much the Adams of three or four decades ago. From the perspective of 2020, Adams’ minimalism looks like a relatively brief flirtation, and more of a means of satisfying his remarkable expressivity than a sign-up to any particular dogma.

He’s undoubtedly America’s most celebrated and most often performed composer. And you can see why, with his colourful, vibrant, deeply expressive music. And with his sometimes disarming blend of flippant humour and deep seriousness: this was the man, after all, whom the New York Philharmonic commissioned to compose a memorial to the victims of 9/11.

Adams’ music features prominently across four concerts in the Scottish Chamber Orchestra’s 2020/21 Season, and the featured works provide some telling insights into the contrasting sides of his musical personality. To begin at the end (or at the beginning), way ahead in March 2021 is one of Adams’ earliest works, and what’s probably his most famous example of ‘pure’ minimalism: Shaker Loops. The piece had a long and troublesome genesis, beginning as an experimental piece for three violins unveiled in a San Francisco loft in 1976, then morphing into a string quartet for the Kronos Quartet, before finding its final form as a string septet, with an alternative version for string orchestra. And if you’re looking for the scurrying repetitions and hypnotic vistas of minimalism in Adams’ music, then this is one place to find them. What strikes listeners about Shaker Loops, however, is the piece’s breathtaking sense of energy, its feeling of rushing headlong forward in time, and the exquisite sheen of its radiant, consonant harmonies.

The Shaker bit of its title refers not only to the ‘shaking’ required from the string players to produce the music’s tremolo effects, but also to the religious sect that had been particularly active in New England, Adams’ childhood home. And it’s hard not to see parallels between the shaking and trembling that notoriously characterised their ecstatic, trance-like worship, and the sense of mounting euphoria generated by Adams’ remarkable music.

Shaker Loops shows Adams the experimentalist, under the influence of archagitator John Cage, sticking a mischievous middle finger up at the strictures and mindboggling complexities of the avant-garde musical thought he’d been taught. But even in those early days, he had his reservations about so-called minimalism. It might be great for generating a hypnotic sense of musical ecstasy, but could it translate into music of emotional subtlety, of developing moods and ideas?

Adams remembers an epiphany in 1976 – the same year the three-violin version of Shaker Loops was premiered – when, driving in the Sierra Nevada foothills in his adopted California with Götterdämmerung blaring from his car stereo, he abruptly realised of the sheer expressive power of Wagner’s music. (Just listen to Adams’ massive semi-symphony Harmonielehre, which virtually quotes Mahler’s Tenth, to hear the impact.)

Yet he had also been immersed in jazz and pop from a young age: his father had played clarinet and saxophone in swing bands since the 1930s, and he remembers rushing from his Harvard lectures on complex serial counterpoint to return to his room to listen to Jimi Hendrix or John Coltrane. Avant-garde complexity, experimental anarchy, Wagner, Mahler, jazz, rock: crucially, Adams quickly realised that all these were highly evolved and immensely complex styles, albeit in their own different ways. And truth to be told, that mix of styles and genres has always been evident in his music. Adams’ 1993 Violin Concerto, which Josef Špaček plays with the SCO in November, sounds almost like a long, free-flowing jazz solo in its long-limbed violin lines, and you can still hear the remnants of minimalist repetitions in its chugging accompaniments.

More directly inspired by jazz, however – not surprisingly – is Adams’ 2013 Saxophone Concerto, which Jess Gillam performs with the SCO in March 2021. Adams followed in his father’s footsteps as a clarinettist in his childhood, going on to perform in several professional East Coast orchestras. So it’s no surprise that he felt a particularly strong connection with his instrument’s half-brother, in a work that draws directly on his early immersion in the music of Coltrane, Charlie Parker, Wayne Shorter and many others. But it’s a chameleon concerto, a piece that doesn’t set out to sound like jazz but nonetheless often does, a work that offsets its smoky, sultry episodes with passages making full use of the dazzling colours of a classical orchestra, Adams’ characteristic pulsing energy pushing everything ever onwards.

There’s a lot going on in Adams’ music. But if you fear you need a doctorate in musicology to appreciate it – well, that won’t be necessary. What really marks out Adams’ music is its deep sense of direct communication and expressivity – part of which, it has to be said, is the composer’s sometimes eyebrow-raising humour. There’s a lot of quirky comedy in the titles he chooses – from his well-known Short Ride in a Fast Machine to his recent piano concerto Must the Devil Have All the Best Tunes?, given its European premiere at the 2019 Edinburgh International Festival. And it’s there, too, in Adams’ music itself, from the audacious, Liberace-inspired excess of his gloriously over-the-top Grand Pianola Music to the hyperactive invention of his Chamber Symphony and its sequel, Son of Chamber Symphony (performed by the SCO in 2018), inspired by the cartoon music of Carl Stalling and Raymond Scott.

There’s a lot of humour, too, in the Adams piece that launches the SCO’s Season in September. The Chairman Dances is what Adams describes as an ‘out-take’ from his opera Nixon in China, in which Mao’s terrifying wife Jiang Qing invites the great Chairman to emerge magically from his iconic portrait and dance with her at a state banquet. With its swooping, movie-style themes, its heart-on-sleeve sentimentality, and even its witty closing imitation of an ancient gramophone slowly winding down, it’s unashamedly funny. But it’s shot through with melancholy, too, and full of the cleverness and depth of meaning that characterise the eclectic but immediate output of one of today’s most fascinating composers.